The present invention relates to physically independent agitators used for mixing liquids, solid/liquid suspensions and powdered solids within containers. More particularly, the present invention relates to agitators for mixing powders with liquids to create a well dispersed, substantially homogeneous suspension.
Agitators are commonly used in aerosol paint cans to mix the pigment with the suspension fluid. Many designs exist which are tailored to optimize mixing action and to agitate hard to reach areas of the paint containers. Various shapes of agitators exist which disperse paint pigment throughout a suspension medium. Multi-pronged agitators, spherical agitators, multi-faceted hemispherical agitators and disc-shaped agitators with conical projections exist for agitation of pigment particles in paint containers. These agitators are typically sealed within an aerosol paint container and activated by shaking the container. Movement of the agitators induced by shaking the container displaces and disperses the pigment particles into suspension. This is necessary because the pigment particles settle to the bottom of the container when the paint has rested in a stationary position for a significant period of time. Due to this specific pigment dispersion application, these agitators are specifically designed for dispersion of an agglomeration of particles at the bottom of a container. These agitators are most often discarded in the paint container in which they are used. Consequently, these agitators do not perform optimally for dispersion of powders which typically float at the top of a suspension liquid before mixing. They are also generally small in size with complex surfaces making them easy to lose and difficult to clean in preparation for repeated use. In addition, the small size and heavy weight result in a small cross-section to screen or disperse powders.
Agitators also exist for powdered food supplements that are added to and mixed with liquids. Baby formulas and nutritional supplements often require an agitation or dispersion device for optimal mixing and dispersion. Often dispersing elements are attached to specific containers for mixing of contents placed therein. These attached or fixed agitators may have a semi-permanent connection to a container or may be manufactured integrally with a given container. However, these attached elements often create cracks and crevices which are difficult to clean. Furthermore, attached devices often do not allow sufficient movement of the dispersing element for optimal mixing. Another disadvantage of known fixed dispersing elements is their inability to be transferred between commonly-used containers.
Powdered compositions for mixing with liquids such as dietary supplements, drink mixes, baby formulas and others are often difficult to mix into a smooth, homogeneous suspension. The powdered composition often clumps forming aggregations of powder surrounded by a thick layer of paste that inhibits liquid from penetrating into the clump. These clumps may float, sink to the bottom of the container or remain suspended at some level in the fluid. Powder may also stick to the sides or bottom of a container and resist mixing by simple shaking. In most cases, an agitator is necessary for complete dispersion of clumps and aggregations on the container walls. No single, known agitation element is effective at reaching clumps and aggregation at the top, middle and bottom of a container while being easily removed from the container for ease of cleaning or for subsequent use in another container.
The present invention relates to improved apparatus and methods for agitation of liquid/powder mixtures during the mixing process. The apparatus of some embodiments of the present invention comprises an object with a wire-frame shape through which liquids and fine-grained solids may pass. The wire-frame object may be constructed of a variety of materials including wound metal wire, molded plastic materials or almost any other material that will substantially retain its shape after repeated impact with a container.
The shape of the agitator object may also vary widely including, but not limited to, cubes, spheres, ellipsoids, pyramids, polyhedrons, cylinders and others. However, the shape must be formed by a wire frame that allows flow of material through and around the object. The flow of material whether liquid or powder, through the object creates turbulent eddy currents within and around the object that break up aggregations of material and disperse particles throughout the suspension medium.
Agitation is improved in some embodiments of the present invention by the use of one or more additional interior objects placed inside a wire-frame object. These interior objects may be solid or may also be wire-frame objects. The additional motion of the interior object inside the primary object creates further turbulence and dispersion which more quickly and effectively mixes the solids with the liquid suspension medium. Impacts of objects within the primary wire-frame object also serve to break up smaller clumps in the mixture.
Because the agitation objects are free to move throughout the mixing container, they are able to reach aggregations of powder at any level in the mixture and create greater turbulence. Initially, powders will accumulate at the surface of the liquid medium and form large clumps. Stationary mixing fins and protrusions are largely ineffective at dispersing these clumps and simple shaking without agitators frequently causes clumps to become more dense and difficult to ultimately disperse into an acceptable particle size. The physically-dependent agitator objects of the present invention, however, may be directed toward the surface accumulations by tilting the top of the container outward and effectuating a spinning action on the container to move the agitators through the accumulations and break them into smaller and smaller masses. After the large clumps have been dispersed, smaller aggregations may still be present in the mixture. These are typically well dispersed throughout the medium and found at every level of the mixture. At this point in the mixing process, the wire-frame agitators may be directed throughout the mixture by random oscillation of the container or by direction to specific areas that require further mixing.
Powder/liquid mixtures are often susceptible to aeration during mixing as simple shaking entraps air in the container under waves at the surface of the liquid causing bubbles to be entrained in the liquid. This may be acceptable for some mixtures, but can be extremely undesirable for others. For example, baby formulas, if entrained with air often cause excessive burping and discomfort for the child consuming the formula. The agitator objects of some embodiments of the present invention are physically independent of the container allowing a user to keep them immersed in the liquid while rotating the container gently. This gentle rotating action causes the objects to roll or tumble around the container thereby dispersing the solids in the suspension without causing air to be entrained in the liquid. This reduces frothing and the consumption of unnecessary air by the consumer of the mixture.
In addition, the rotation of the agitator causes a mixing turbulence or screening effect which aids in mixing. Because the liquid passes through the rotating agitator, a chopping action is created which breaks up chunks better than a solid agitator. The agitator within an agitator embodiment increases the chopping action. As some of the breaking up of constituents occurs as the agitator collides with the walls of the container, the collisions between the agitator within an agitator embodiment also increase the breaking up action. The relatively large size of the agitator not only increases surface area for collisions, but also prevents swallowing of the agitator when the liquid is consumed. The size of the agitator or number can be altered to fit the container. Small containers will necessitate small agitators.
Accordingly, it is an object of some embodiments of the present invention to provide apparatus and methods for improved mixing of powders and liquids.
It is another object of some embodiments of the present invention to provide apparatus and methods for better reducing and dispersing clumps in mixtures.